Drill jar



June 1 1926.

G. A. MONTGOMERY DRILL'JAR Filed Feb. 25, 1924 Patented .lunev l, 1926.v

UNITED STATES PATENT OFFICE.

GUS'AVUS A. MONTGOMERY, OF TITUSVILLE, PENNSYLVANIA, ASSIGNOR TO TITUS-'VILLE FORGE COMPANY, 0F TITUSVILLE, PENNSYLVANIA, A CORPORATION OFMARYLAND.

nmLr. JAR.

Application-med February 2,5, 1924. Serial No. 694,855.

This invention relates generally to the fishing and drilling toolsemployed in connection with oil well drilling operatlons, b ut moreparticularly to improvements in drill ars.

J Its chief object is to provide a tool of this character which isprovided with a plurality of knocking heads and in which the parts ofthe jar are so constructed and arranged that they form a self-containedunit.

Another object of the invention is to pro vide a nonweldable jar whichis strong and rugged in construction and efficient in o peration, andwhich is so constructed that its parts are prevented from swivelmgrelatively to each other.

A still further feature of the invention resides in the novel methodemployedfor making the jar.

ln the accompanying drawings: Figure 1 is a fragmentary sectionalelevation of a tool constructed in accordance with my invention. Figure2 is a sectional elevation of the jar-body or cylinder. Figure 3 is across section on line 33, Fig. 1. Figure 4 is a cross section on line 44, Fig. 2. Figure 5 isa detached side elevation of the jar or plungershown at .right angles to that illustrated in Fig. 1. Figure 6 is afragmentary perspective view of the jar or plunger.

Similar characters of reference indicate corresponding parts throughoutthe several views.

The improved tool comprises two parts, viz: a jar-body or cylinder l0closed at one end and open at its opposite end; and a plunger or jar 11mounted to reciprocate in said jar-body. Extending from the open upperend of the jar-body to a point near the closed lower end thereof is acentral bore preferably including a plurality of portions 12substantially circular in cross section and a like number of portions 13of cruciform or other similar shape in cross section, as shown in Figs.3 and 4. These two portions of the bore are alternately disposed inaxial alineme-nt as shown in Fig. 2, the uppermost cruciformbore-portion being located at the extreme upper end of the jar-body.4

By this arrangement, inwardly-facing shoulders or knocking heads 14 areprovided at 'the junction or intersection of the respective portions 12,13, with one another, these shoulders being segmental or rib-like `inform due to the cross-sectional shapes of said portions. If desired,openings or slots 15 extending lengthwise of the jar-cylinder may beformed in the walls of the cylindrical portions 12 for thepurpose ofpermitting the entrance and discharge of mud, sanld, water, &c duringthe operation of the too The plunger or jar proper is shaped to fit theportions 12, 13 of the jar-body. For this purpose, it is provided with aplurality of substantially cylindrical jar-portions or pistons 16 whichare adapted to slidably engage the corresponding portions 12 of thejar-body, and a like number of channeled guide-portions 17 of-cruciform'shape in cross section which are adapted to slidably fitwithin the corresponding portions 13 of said jar-body. At the junctionof the jar-portions with their guide portions are formed segmentalshoulders or projections 18 which are adapted to strikeV thecorresponding shoulders 14 of the jar-body during the relativereciprocation of the latter and the jar proper. The upper end of thelatter is provided with the customary tapered attaching pin 19.

The method of making the jar cylinder and assembling the plunger jarwithin the same is preferably as follows:

After the4 jar-cylinder has been properly shaped as to its externaldimensions, the same is bored and counterbored to produce thecorresponding portions 13, 12, the size of the main bore beingapproximately equalV to the diameter of the circle inscribed within thecruciform shaped portions 13 and the diameter of the counterbores beingthe same as that of the cylindrical portions 12. The main bore, it willbe understood, extends from the open end of the jar-cylinder to thebottom of its-lowerm'ost cylindrical portion 12. The longitudinal slots15 are. now cut in the diametrically opposite sides of the jar-cylinderand longitudinal saw slits 2O are also cut therein in line with saidslots. The two halves of the jar-cylinder thus formed are then separatedor distended into separated position, the portions 13 are then milled tosuch form that when the half-sections are brought together, suchportions are substantially cruciform shape in cross section.

While the halvesof the jar-cylinder are in their distended position, theplunger is then placed therein with its jar portions 16 engaging thecylindrical portions 12 of said cylinder and its cruciform guideportions 17 fitting the corresponding portions 13 of the cylinder. Thehalves of the latter are now brought .together and permanently united bya ring 21 shrunk or otherwise fastened at 4the open end ot' the cylinderand by electrically welding the joints formed by the saw slits 20. Thisstep coinpletes the assembling of the tool, and the same is now readyfor use.

Both parts of the tool are preferably made of alloy steels which can beelectrically welded but which are ordinarily not weldable in theblacksmith shop.

This improved drill jar is simple, yet strong and durable inconstruction and by making the jar-cylinder and jar-plunger in themanner herein shown and described, a plurality of knocking heads areprovided which result in an increase in the area of the wearing surfacesof these parts and also prolong the life of the tool. Furthermore, thecruciforin cross section of the guide portions of the plunger and thecorresponding portions of the cylinder adds materially to the strengthof the tool and also prevents any swiveling action of its parts relativeto each other.

I claim as my invention:

1. A tool of the character described, comprising a jar-body having aplurality of alternately arranged large and small bores disposedsubstantially in axial alignment,

the small bores being defined by segmental-v ly-shaped ribs forminginternal knocking- 'heads between the respective bores, and a plungerhaving a plurality of alternately arranged jar portions and guideportions operating in said large and small bores respectively, the guideportions containing channels engaging the ribs of said small bores, theresulting shoulders formed between said jar portions and said channeledguide portions bein arranged for engagement with the knoc {ing-heads ofsaid jarbody.

2. A tool of the character described, coinprising a jar-body having aplurality of alternately arranged bores of substantially cylindrical andcruciform shape in cross section, respectively, and Jforming segmentalknocking-heads between them, and a plung-` er having a plurality vofalternately arranged jar portions and guide portions correspond-1` ingin cross section to the bores of said jarbody and operating in thesaine, said plunger having segmental shoulders formed between the jarportions and the guide portions for engagement with the knocking headsof saidjar-body.

3. The method of making a tool of thev character described having ajar-body and a plunger including jar portions and guide portions ofcruciform shape in cross section operable therein, which consists informing alternately arranged large and sinall'bores' tions with its jarportions engaging the large bore of the jar-body and its guide portionsengaging the cruciform-shaped bores of said jar-body, and then bringingsaid half-sections together about the plunger and uniting them. l

GUSTAVUS A. MONTGGMERY.

